LABO — Acoustics, evolved.

THD+N · 1 kHz Loopback

UMC1820 · Out 3 → In 3 · 48 kHz · 24-bit

THD+N (referred to total)

−77.2dB

0.0138 % · AP / IEC convention

Fundamental

−20.61dBFS

1,000.00 Hz

Harmonics

−90.0dB

2nd dominant

Noise

−77.4dB

−98.0 dBFS broadband

Spectrum dBFS per bin · log frequency · 4.00 s coherent window

Fundamental−20.61 dBFS 2nd−110.6 dBFS Floor −148 dBFS/bin

Harmonics Orders up to 23 are in band at 48 kHz

OrderFrequencyLevel (dBFS)Rel. fundamental

2nd2,000 Hz−110.6−90.0

3rd3,000 Hz−132.8−112.2

4th4,000 Hz−136.0−115.4

5th5,000 Hz−128.6−108.0

6th6,000 Hz−140.7−120.1

Run 1786295311203-0 · Captured 4.00 s · 0 samples dropped · thdn/1 · Full Nyquist band, not band-limited to AES17

Admissibility

ConclusiveAll four preconditions hold.

Preconditions

Software gainOutput 1.00 · Input 1.00

Clock alignment0 frames jitter

Coherent window2,900 whole cycles

Calibrationcal-2026-08-01 · 22 days left

Signal Chain

DeviceUMC1820

RouteOut 3 → In 3

IO offset1,112 frames

Round trip1,221 frames

Beyond scheduling2.27 ms

Evidence

6c8f9d21…2090b703Archived

THD+N · 1 kHz Loopback

UMC1820 · Out 3 → In 3 · 48 kHz

THD+N (referred to total)

−51.3dB

Not conclusive Conclusive

Shown for diagnosis only

0.0138 % · AP / IEC convention

Spectrum

Admissibility

!

Not conclusive1 of 4 preconditions failed.

ConclusiveAll four preconditions hold.

Preconditions

Software gainOutput volume 0.063 · −24.0 dB

Software gainOutput 1.00 · Input 1.00

Clock alignment0 frames jitter

Coherent window2,900 whole cycles

Calibrationcal-2026-08-01 · 22 days left

The system output volume scales the signal before it reaches the converter. Until it is 1.00, no absolute level from this device can be trusted.

THD+N vs Level · 1 kHz

UMC1820 · Out 3 → In 3 · 6 points · 3.0 s each

THD+N and its parts THD+NHarmonicsNoise

Level (dBFS)THD+N (dB)HarmonicsNoise

THD+N vs Level · 1 kHz

UMC1820 · Out 3 → In 3

Agent Level sweep

Find the best operating point for this loopback. Stop if anything stops being conclusive.

Verified loopback routingOut 3 → In 3 · tone fraction 100.0 %

Measured at −20.6 dBFSTHD+N −77.2 dB · conclusive

Measured at −12.7 dBFSTHD+N −77.2 dB · conclusive

Raise generator to −6 dBFSWaiting for your approval

Measured at −6.6 dBFSTHD+N −73.3 dB · conclusive

Best operating point −20.6 dBFSGenerator returned to −20.6 dBFS

The agent can measure on its own. Anything that changes hardware state waits for you.

Runs

142 measurements · 138 conclusive

Search runs

TimeMeasurementResultAdmissibility

Acoustics, evolved.

Carte

Coécho